/// <summary>Handles the LayoutUpdated event of the Thumbnail image
/// Actually, we really just ask Windows to paint us at our new size...
/// </summary>
/// <param name="sender">The source of the event.</param>
/// <param name="e">The <see cref="System.EventArgs"/> instance containing the event data.</param>
private void Thumbnail_LayoutUpdated(object sender, EventArgs e)
{
if (IntPtr.Zero.Equals(_thumb))
{
InitialiseThumbnail(WindowSource);
}
else if (null != _target)
{
if (!_target.RootVisual.IsAncestorOf(this))
{
//we are no longer in the visual tree
ReleaseThumbnail();
return;
}
GeneralTransform transform = TransformToAncestor(_target.RootVisual);
Point a = transform.Transform(new Point(0, 0));
Point b = transform.Transform(new Point(ActualWidth, ActualHeight));
var props = new NativeMethods.ThumbnailProperties
{
Visible = true,
Destination = new NativeMethods.Rect(
2 + (int) Math.Ceiling(a.X), 2 + (int) Math.Ceiling(a.Y),
-2 + (int) Math.Ceiling(b.X), -2 + (int) Math.Ceiling(b.Y)),
Flags = NativeMethods.ThumbnailFlags.Visible | NativeMethods.ThumbnailFlags.RectDestination
};
NativeMethods.DwmUpdateThumbnailProperties(_thumb, ref props);
}
}
/// <summary>Updates the thumbnail
/// </summary>
private void UpdateThumbnail()
{
if (IntPtr.Zero != _thumb)
{
var props = new NativeMethods.ThumbnailProperties
{
ClientAreaOnly = ClientAreaOnly,
Opacity = (byte) (255*Opacity),
Flags = NativeMethods.ThumbnailFlags.SourceClientAreaOnly | NativeMethods.ThumbnailFlags.Opacity
};
NativeMethods.DwmUpdateThumbnailProperties(_thumb, ref props);
}
}
/// <summary>Initialises the thumbnail image
/// </summary>
/// <param name="source">The source.</param>
private void InitialiseThumbnail(IntPtr source)
{
if (IntPtr.Zero != _thumb)
{ // release the old thumbnail
ReleaseThumbnail();
}
if (IntPtr.Zero != source)
{
// find our parent hwnd
// [System.Windows.Interop.HwndSource]::FromHwnd( [Diagnostics.Process]::GetCurrentProcess().MainWindowHandle )
//target = HwndSource.FromHwnd(System.Diagnostics.Process.GetCurrentProcess().MainWindowHandle);
_target = (HwndSource)PresentationSource.FromVisual(this);
// if we have one, we can attempt to register the thumbnail
if (_target != null)
{
int result = NativeMethods.DwmRegisterThumbnail(_target.Handle, source, out _thumb);
if (0 == result)
{
var props = new NativeMethods.ThumbnailProperties
{
Visible = false,
ClientAreaOnly = ClientAreaOnly,
Opacity = (byte)(255 * Opacity),
Flags = NativeMethods.ThumbnailFlags.Visible | NativeMethods.ThumbnailFlags.SourceClientAreaOnly
| NativeMethods.ThumbnailFlags.Opacity
};
NativeMethods.DwmUpdateThumbnailProperties(_thumb, ref props);
}
}
}
}
